Conventional retailer websites allow shoppers to browse through a wide variety of products available for sale online. Each retailer website typically hosts multiple product listing webpages that offer various products for sale. Moreover, each retailer website generally maintains its own inventory of products. These different inventories may be stored using different taxonomies for each retailer website. It can be difficult, therefore, to compare products between websites or perform other comparative functions because it can be difficult to determine with precision whether a particular product on one retailer website is identical to a particular product on another retailer website.